A traditional multicolored stain is desirable for staining cell smears for certain cytological analyses. It is advantageous because the nucleus and the cytoplasm of the stained specimen are colored differently. In one preferred staining practice, the cytoplasm is transparent, whereas the nucleus is transparent to opaque. This staining pattern allows the cytologist to distinguish cells which are morphologically abnormal. In addition, cytologists find the variety of colors of the traditional stains, particularly the Papanicolaou stain, helpful to reduce eye strain and to aid diagnosis.
However, the traditional stains, including the Papanicolaou stain, are difficult for an automated system to analyze. The variety of colors in the cytoplasm from traditional stains, which are straightforward for the human eye to distinguish, are not readily analyzed with automated systems because they contrast to varying degrees with the traditional blue hematoxylin stain of the nucleus. The varying contrast makes automated analysis unreliable.
A number of researchers have developed algorithms in an attempt to attain automated analysis of cells stained with the Papanicolaou stain. Most techniques involve the use of various instrumental artifacts, such as different colors of light, filters, and color television cameras. Many require a high level of sophistication that is costly in terms of hardware and software. Further, these approaches have not proven accurate and reliable enough to be widely used in clinical cytological and histological diagnoses.
It is an object of the present invention to provide a method of cellular analysis in which the cells are multicolored and the nuclear portion is clearly distinguishable from the cytoplasmic portion both with automated equipment and with manual vision analysis.
It is a further object to provide a method of cellular analysis in which the characteristics of the stained cells can be accurately determined with both manual and automated analysis procedures.
Other objects of the invention will in part be obvious and will in part appear hereinafter.